What is the partial pressure of argon, par, in the flask? express your answer to three significant figures and include the appropriate unit?

Given which are missing in your question:
the flask is filled with 1.45 g of argon at 25 C° 
So according to this formula (Partial pressure):
PV= nRT
first, we need n, and we can get by substitution by:
n =  1.45/mass weight of argon
   = 1.45 / 39.948 = 0.0363 mol of Ar
we have R constant = 0.0821
and T in kelvin = 25 + 273 = 298
and V = 1 L
∴ P * 1 = 0.0363* 0.0821 * 298 = 0.888 atm